Sharon Cheng, of Save Our Surgery (SOS), which campaigned for surgery to be resumed at Leeds, said:
"Sir Roger Boyle's comments of this morning are extremely unhelpful and undermine the progress made over the last few days to begin to rebuild heart patients' families' trust and confidence in the Leeds children's heart surgery unit.
"His implication that surgery should not have been resumed at Leeds contradicts everything we have heard from NHS England, the Care Quality Commission and NHS medical director, Sir Bruce Keogh, who have all stated unequivocally that the unit is safe, hence their resumption of surgery.
"Sir Bruce himself went on record this week saying he would feel comfortable having his child operated on in the unit.
"Let me be absolutely clear - the Leeds unit would not be operating if there were any concerns whatsoever about mortality rates or anything else.
"Once again, this is an example of Sir Roger Boyle speaking out without due regard to the necessary process, the verified facts or the implications of his actions on patients and their families.
"He is not an impartial party in regards to Leeds and as an adviser to the Safe and Sustainable review, we do question his motives."